ACR LGT ACFT NOSEWHEEL STRUT IN THE DOWN POS AFTER TKOF RESULTING IN THE FLC RETURNING TO LAND.

Narrative

ON LGT ACFT FLT OF ACR AIRLINES; EXPERIENCED AN AIR RETURN DUE TO THE NOSE LNDG GEAR NOT BEING ABLE TO RETRACT AFTER TKOF. UPON RETURN TO ITS STATION OF ORIGINATION; MIA; IT WAS DETERMINED THAT THE CAUSE WAS A NOSE LNDG GEAR DOWN LOCK PIN WHICH WAS LEFT IN PLACE BY MYSELF DURING THE PREVIOUS OVERNIGHT STAY (AS I INSTALLED IT AS A SAFETY PRECAUTION TO AVOID INADVERTENT RETRACTION WHILE I PERFORMED A FULL SVC ON THE NOSE LNDG GEAR STRUT). I BELIEVE THAT A FACTOR WHICH CONTRIBUTED TO MYSELF AND THE FLC'S SO MISSING THE PIN BEING INSTALLED WAS THE INABILITY TO SEE THE RED WARNING FLAG WHICH I WRAPPED AROUND THE PIN ITSELF IN ORDER TO KEEP IT IN PLACE. NORMALLY; A LANYARD CLIP IS PART OF THE PIN AND IT IS USED TO KEEP THE PIN IN PLACE. THIS LANYARD CLIP ASSEMBLY WAS MISSING ON THE PARTICULAR PIN WHICH LED ME TO USE THE RED FLAG TO KEEP PIN IN PLACE. ALTHOUGH THERE WAS A DEG OF NEGLECT ON MY AND THE SO'S PARTS; I BELIEVE THAT A PROPERLY EQUIPPED PIN WOULD HAVE KEPT THE FLAG IN BOTH OF OUR VIEWS.